"Reading the paper, watching the news, walking down the street, gossiping with friends — our lives are replete with opportunities to hear about or witness others' misfortunes. How people respond to others' pain, however, depends on their preexisting prejudices toward the target of the misfortune," the authors, Mina Cikara of Carnegie Mellon University and Susan T. Fiske of Princeton University, write.

We already knew that people were more likely to take pleasure in others' misfortune (which is called schadenfreude, pronounced scha-den-freu-de) during three conditions:

When it benefits you.

When it seems like the person deserved it.

When it happens to someone you envy.

It seems that the last condition, envy, is applied much more broadly than we realized thanks to stereotyping.

Cikara and Fiske, Ann NY Acad Sci, 2013People are more likely to envy people who are high in competence but low on warmth.

We decide who to envy by the stereotypes that we've applied to them — how "warm" and "competent" they are. Using these stereotypes the researchers split groups into four types: those who elicit pity, disgust, pride, or envy.

These stereotypes let us judge and envy people we've never met, and therefore, we can delight in the misfortunes of celebrities who we don't actually know instead of empathizing with them.

The researchers did four experiments to determine if their theory is sound.

1. They matched pictures of people in the categories in the chart above to positive, negative, and neural events that happened (these included statements like "won a $5 bet," "got soaked by a taxi," and "went to the bathroom"). They showed the images and statements to participants while measuring their face movements to determine their emotional state.

When the object of envy (say a man in a business suit) encountered misfortune (say, was peed on by a dog) the participants smiled more than when something good happened to the businessman.

2. In another experiment, they gave the participants a "Fear Factor"-type scenario, in which they got to punish the other players with a mild shock or give just one a bigger shock. They were asked how willing they would be to volunteer each of the four stereotypes above for the larger punishment. In fitting with the researchers theory, they volunteered the "envy" target — a man in a business suit — to receive the large shock.

3. The researchers then tried to change the participants view of these "enviable" characters by giving them more information, thereby transforming the businessman into one of the other groups. They told people that the man was advising small businesses for free (pride), was using his last bit of money to fund his drug habit (disgust), or had lost his job but was pretending to go to work (pity). Knowing this information, the participants were less likely to delight in his misfortunes. These scenarios didn't impact their feelings toward the other groups.

4. To test if social constraints were holding people back from expressing their true inner delight in the misfortunes of those they envy, the researchers turned to a historic baseball conflict: The New York Yankees versus the Boston Red Sox. Surprisingly, schadenfreude is generally acceptable (and even desirable) in sports, politics, and celebrity gossip. Participants were screened for "intense fandom," then played videos of their team, the rival team, and a neutral team (the Orioles) either making or missing a play. They rated their pleasure, pain, and anger during each clip.

What was interesting was that fans were happy when their rivals failed to make a play against the Orioles — delighting in misfortune that didn't even benefit them (what the researchers called the pure schadenfreude condition).

They can even see this schadenfreude in brain scans of fans. Usually when we are in pain or see someone else in pain brain scans show activity in the anterior cingulate cortex and the anterior insula. When it's our competition that is in pain, though, these areas aren't lit up as much.

"Schadenfreude may play a central role in the escalation of intergroup conflict," the authors write. "This suggests that individual group members need not have a personal history of conflict in order to feel motivated to harm one another, particularly if group relations are already hostile."

This builds on previous research, which found that we all have a little sadist in us. That research found that more than half of people had "sadistic personality traits." These personality traits might be stronger when the pain we are observing is being inflicted on someone we envy or someone from a different social group.

"In the United States, stereotypes regarding status and competitiveness breed dislike for 'model minorities' (e.g., Jews, Asians) and successful subordinate group members (e.g., black professionals, career women)," the authors note. "It is not a coincidence that genocide and mass violence have often targeted ethnic groups that appear in the envy quadrant."